I do all the time too. Very similar and yes a bit more lemon then lime. Sometimes dependent on the marinade I will add a small amount like 1/4 of a teaspoon of honey if I subbed lime for lemon. It tends to balance it out, but again, it really depends on the recipe. I also have used 1/2 lime and 1/2 orange instead of lemon for some marinades which seems to work well.

This works in vinaigrettes or marinades. If lemon was the main component in a dish I would be careful substituting the flavors. Mexican, Caribbean dishes or Thai dishes (just as an example) without lime to me wouldn't be right using lemon or orange.

Not too much difference. I buy limes out of habit because except for a couple northern Mexico states, lemons are unavailable. Lemons are much better for zesting because the rind has much more oil than limes.